Means for controlling relative position of elements in a circular knitting machine



Dec. 6, 1960 M. L. SHIPWASH 2,962,882

MEANS FOR CONTROLLING RELATIVE POSITION 0F ELEMENTS IN A CIRCULAR KNITTING MACHINE Filed 391312. 28, 1959 4 Sheets-Sheet 1 Fi i INVENTOR.

By MAC/f 1.. SH/PWASH m @zw Dec. 6, 1960 Filed Sept. 28, 1959 SHIPWASH 2,962,882

RELATIVE POSITION 0F 4 Sheets-$heet 2 I 90 ,I III Z 34 J 16' i I 14 g I I @82 i I: l

k} li-| 1 *5 lfl E l 1 2' i: E I ll 1 I I 22 104 i Z4 INVENTOR.

Mark 1.. sir/Puma BY Afro/ E VJ Dec. 6, 1960 2,962,882

M. L. SHIPWASH MEANS FOR CONTROLLING RELATIVE POSITION OF ELEMENTS IN A CIRCULAR KNITTING MACHINE Filed Sept. 28, 1959 4 Sheets-Sheet 5 EN TOR.

y war 1. .smpwam Dec. 6, 1950 2,962,882

M. L. SHIPWASH MEANS FOR CONTROLLING RELATIVE POSITION 0F ELEMENTS IN A CIRCULAR KNITTING MACHINE Filed Sept. 28. 1959 4 Sheets-Sheet 4 INVENTOR. MACK .L. SH/PWASH United States Patent MEANS FOR CONTROLLING RELATIVE POSITION OF ELEMENTS IN A CIRCULAR KNITTING MA- CHINE Mack L. Shipwash, Salisbury, N.C., assignor of one-half to James A. Summers, Salisbury, NC.

Filed Sept. 28, 1959, Ser. No. 842,807

4 Claims. (Cl. 66-55) The present invention relates to an improvement in circular knitting machines, and more particularly to means for stabilizing the needle cylinder of a circular knitting machine in its proper operating positions so that uniform stitches will be knit and the articles produced will be of a uniform size and shape.

The circular knitting machine, which is now and has long been in commercial use, knits tubular articles such as ladies hosiery by feeding yarn through a knitting head to needles and singers mounted in a cylinder that rotates with respect to the knitting head. The needles and sinkers are manipulated by cams as the cylinder rotates so as to form the yarn into stitches.

The cylinder is supported on a tube which is raised and lowered to change the position of the cylinder with respect to the cams and thereby change the position of the sinkers with respect to the needles. When the cylinder is raised the needles and sinkers form loose stitches and when the cylinder is lowered the needles and sinkers pull the stitches tighter. Thus the sizes of the stitches and therefore the diameter of the tubular article can be carried by controlling the position of the cylinder. Also, the loose stitch is desirable to accommodate heavier yarns.

When knitting ladies hosiery, for example, the cylinder is in its highest position during the knitting of the heel and toe in which a heavy yarn is used and the cylinder is oscillated, rather than rotated, to form the desired configuration. Also, when knitting the welt portion of the hose the cylinder is in one of the raised positions to accommodate the heavy welt yarn and form the large stitches that result in the large diameter desired at the top of the hose. As the leg portion of the hose is knit, beginning at the bottom of the welt, the cylinder is initially lowered to handle the finer yarn and is gradually lowered further to reduce the stitch size and thus reduce the diameter of the hose to conform to the configuration of a leg. The cylinder is in its lowest position when knitting the relatively small diameter of the foot portion.

On a conventional circular knitting machine, such as the well known Scott and Williams, Inc., Model K machine, the distance between the highest and lowest cylinder positions may be approximately of an inch, and the cylinder may move in increments as little as of an inch from one position to the next. However, due to the relatively high speed of rotation, the cylinder does not always drop down with the tube but remains in a raised position or flutters upwardly from the proper position.

When the cylinder floats the needles and sinkers knit stitches that are larger than desired, which results in a larger diameter than desired and, more importantly, an increase in the length of the article. If the floating or fluttering occurs during the knitting of an appreciable number of courses, the length of the article knit may be sufliciently longer than the standard length so that the article is unsatisfactory and must be rejected.

This problem of non-uniformity of the length of articles knit is present when knitting with any yarn size, but is accentuated when knitting with relatively fine yarns as the total number of courses in the article is greater than with heavy yarns and thus there are likely to be more non-uniform courses in the article with :a resulting opportunity for greater variance between the length of articles. For example, 15 denier yarn, which is the predominant yarn size for ladies hosiery at the present time, requires from l5-20% more courses per article knit than 30 denier yarn. Ladies hosiery of 15 denier yarn made to size 10 /2, the most common hose size, requires about 220 lengths at 12 courses per length, or approximately 2,640 courses. The leg portion alone requires about lengths or 1200 courses. Thus, it is obvious that if the cylinder floats but a few thousandths of an inch for only a small percentage of courses the non-uniformity in length can be measured in inches.

This problem of non-uniformity in length is also particularly pertinent in infants goods, such as socks, where in the total number of courses is very small. Thus, in knitting one sock it is possible that little or no cylinder floating will occur, whereas in knitting another sock the cylinder may float for a period representing a large percent of the total courses in the article resulting in a large percentage variance in the lengths of the articles.

In addition to the non-uniform length resulting from floating and fluttering of the cylinder, there is a serious problem of needle damage. When the cylinder flutters or floats, the needles tend to move with the cylinder, and, if the needles are floating as they pass a point on the cam at which the cam divides into two pathways for control of the needles during oscillating knitting of the heels and toes, there is a likelihood of the butts of the needles striking the point of the cam, either breaking the needles or bending the butts.

Various modifications have been attempted to overcome this cylinder floating problem but without complete success. On several types of circular knitting machines, including the above mentioned Scott and Williams, Inc. Model K, a bracket is fixed to the tube and extends upwardly over the sinker cap, which is seated on the top of the cylinder. A set screw or finger extends down into contact with the sinker cap and is adjustable to hold down the sinker cap and cylinder. This apparatus produces satisfactory results when a single yarn size is used, but it does not prevent floating or fluttering when diflerent yarn sizes are used and when the cylinder is oscillated during a portion of the knitting operation. The set screw must be adjusted to a tolerance sufiicient to accommodate the heavy yarn and to permit oscillation of the sinker cap, which oscillates when the cylinder oscillates, but, when the machine shifts to knit a portion of the article with a finer yarn, the smaller yarn diameter requires a closer tolerance to avoid floating or fluttering, and since the set screw is still in the original wide tolerance position there is room for the cylinder to float or flutter, with a resulting non-uniformity in the lengths of the articles and a possibility of damage of the needles.

The present invention provides a means for stabilizing the cylinder in its various operating positions and automatically adjusts the tolerance to provide optimum uniformity results during knitting at each position of the cylinder. The construction includes a rocker member pivotally mounted on the bed plate of the knitting machine, which bed plate is fixed to the knitting machine and guides the cylinder as it moves vertically through the bed plate. The upper arm of the rocker member extends upwardly and has a finger extending over the sinker cap with a roller tip in contact with the sinker cap. The lower arm of the rocker member extends downwardly and is biased against a bracket fixed to the tube by means of a spring that has one end secured to the lower rocker arm and the other end secured to a base plate that is fixed to the machine. The lengths of the rocker arms are related such that the distance from the pivot point to the point at which the roller tip contacts the sinker cap is greater than the distance from the pivot point to the-tip of the lower rocker arm in contact with the bracket on the tube.

Thus, when the tube is raised, the roller tip at the end of the longer upper rocker arm will raise more than the tip of the lower rocker arm and therefore will move more than the cylinder, increasing the tolerance so that the heavier yarn size and the oscillation of the sinker cap and cylinder will be accommodated. Also, the cylinder oscillates in the raised position to knit the heel and toe portions and since the oscillation is at a significantly lower speed than the speed at which the cylinder is rotated when knitting in the lowered positions, there is less tendency for the cylinder to float or flutter and therefore a wider tolerance is acceptable. When the tube is lowered the roller tip will move down more than the cylinder, reducing the tolerance, which is desirable since a finer yarn is used during the knitting at the lower positions.

, Therefore, the present invention stabilizes the cylinder and prevents fluttering or floating and thereby produces a uniform article and eliminates damage of the needles.

A further advantage inherent in the present invention is that it is simple and inexpensive and can be attached to existing machines by merely substituting it for the fixed bracket, or it can be easily incorporated in knitting machines during the original manufacture thereof with little or no increase in cost.

Other and further features and advantages of the present invention will be apparent from the following description and drawings, in which:

Fig. 1 is a fragmentary front elevational view of a circular knitting machine including the preferred embodiment of the present invention;

Fig. 2 is a fragmentary side elevational view of the knitting machine of Fig. 1;

Fig. 3 is an enlarged front elevational view of a portion of Fig. 1 shown partially in section; and

Fig. 4 is a fragmentary top plan view of the left-hand portion of Fig. 1.

Although the drawings show the preferred embodiment of the present invention attached to a particular knitting machine, it is to be understood that the invention is ap plicable as Well to other types of machines and as the machine illustrated is of conventional design the elements will not be described in detail except as pertains to the present invention.

The knitting machine has a supporting framework 12 upon which all of the other elements are supported. The drive transmission mechanism 14 is mounted on the framework 12 and is driven by rotation of the pulleys 16 by a belt (not shown) from a power shaft (not shown). The drive transmission mechanism 14 includes various gear trains and clutches which transmit rotation and oscillation to the knitting elements by means of a driven bevel gear 18, and transmit rotation to the cam drum 20 by means of the spur gear 22. The operation of the drive transmission mechanism is controlled by the indexing chain 24, in'a conventional manner.

A base plate 26 is fixed to the supporting framework 12 below and extending to the left of the drive mechanism 14 and supports the tube 28 by means of an adjustable screw 30 threadably mounted in a bracket 32 fixed to the tube. The screw 30 is adjustable to determine the lowest position of the below-described knitting cylinder.

Also fixed to the supporting framework 12 and extending to the left thereof, but above the drive mechanism 14, is a bottom bed plate 34 that is vertically aligned with the base plate 26. This bottom bed plate 34 has an annular recess and a circular center opening defined by an annular depending flange 36 within which the top of the tube 28 is received and is permitted to move up and 4 down. A top bed plate 38 is rotatably seated in the annular recess and circular opening of the bottom bed plate 34 and has its outer edge 40 formed as a bevel gear which mates with and is driven by the bevel gear 18 of the drive mechanism 14, which bevel gear extends through a slot 42 in the bottom bed plate 34. The central portion 44 of the top bed plate 38 extends upwardly in a cylindrical configuration to form a seat for the knitting cylinder 46.

The knitting cylinder 46 is supported on three equally spaced pins 48 which extend through holes in the top bed plate 38 and rest on top of the tube 28. Thus the cylinder is raised and lowered with the tube 28 and is rotated or oscillated with the top bed plate 38. Needles 50 are mounted around the periphery of the cylinder 46 and are separated by walls 52. The needles 50 have butts 54 which extend outwardly into engagement with the cam surfaces of a cam box 56 that is fixed to the bottom bed plate 34 above the top bed plate 38. Thus, the needles 50 are raised and lowered as the cylinder rotates to perform the knitting operation.

A plurality of sinkers 58 are radially mounted around the top of the cylinder between the needles 50 and are moved in and out by engagement with the cam surface of a sinker cap 60 that is seated on the upper flange 62 of the cylinder 46. This sinker cap has an outer dependinfi flange 64 that mates in an annular recess in the upper flange 62. An L-shapedcl'amp 66 extends from the'sinker cap 60 under the cylinder flange 62 to hold the sinker cap on the cylinder 46. The sinker cap 60 has a pair of spaced outwardly extending lugs 68 that have opposing set screws 70 mounted therein. These set screws 70 are positioned to contact a fixed post 72 that extends upwardly from the bottom bed plate 34 between the lugs 68 and thereby prevents rotation of the sinker cap 60. However, the set screws 70 are adjustable to provide a spacing sufficient to permit oscillation of the sinker cap 60 when the cylinder 46 oscillates, which is necessary to alternate the position of the sinker cap cam during each stroke of the cylinder when knitting the heels and toes.

The knitting head 74 is hinged to the top of a rear post 76 and can be swung into and out of an operating position adjacent the top of the cylinder 46. The knitting head receives the yarn from the cones 75 and feeds it to the needles 50 and sinkers 58.

The raising and lowering of the cylinder is accomplished by a two armed lever 78 which is pivotally secured to the supporting framework 12. The lower arm 80 of the lever 78 rides on the above-mentioned cam drum 20 and has four adjustable screws 8'2 that follow the cam surfaces of the drum. The upper arm 84 .of the lever 78 abuts the underside of a bracket 86 fixed to the tube 28 to impart vertical movement to the tube 28 in accordance with the movement of the screws 82 on the cam surfaces of the drum 20.

The above described construction is conventional in the circular knitting machine art and it is this conventional construction that the present invention is attached. The present invention comprises a rocker member 88 pivotally mounted on a bracket 90 extending from the bottom bed plate 34 for pivotal movement in a vertical plane. The upper arm 92 of the rocker member 88 extends upwardly to a point above and to the side of the sinker cap 60 and has a finger 94 declining toward the sinker cap 60 and terminating in a roller tip 96 that is in contact with the top of the sinker cap 60. The roller tip 96 is freely rotatable on a radial axis with respect to the sinker cap so that there will be little or no resistance to the oscillation of the sinker cap.

The lower arm 98 of the rocker member 88 extends downwardly under the bottom bed plate 34 and terminates in contact with a vertically adjustable screw 100 extending from a bracket 102 fixed to the wall of the tube 28. The screw 100 is adjustable to vary the tolerance between the roller tip 96 and the sinker cap 60. The lower arm 98 is biased against the screw 100 by a helical spring 104 that has one end secured to the end of the lower arm 98 and its other end secured to the fixed base plate 26 upon which the tube 28 is supported. The spring 104 not only biases the lower arm 98 against the screw 100 and thus positions the roller tip 96 with respect to the sinker cap 60, but it also urges the tube 28 downwardly for proper positioning on the base plate 26 or the lever arm 84, thereby preventing vertical deviation of the tube.

The lengths of the upper rocker arm 92 and the lower rocker arm 98 are related to produce a greater distance between the pivot point and the point of contact of the roller tip 96 with the sinker cap 60 than between the pivot point and the point of contact of the lower rocker arm 98 with the screw 100. Thus, when the tube and cylinder move downwardly from the raised position at which relatively coarse yarn is knit, the roller tip 96 will move a greater distance than the sinker cap 60 thereby reducing the tolerance and preventing floating or fluttering of the cylinder when knitting with the fine yarn. On the Scott and Williams, Inc., Model K machine, referred to previously, excellent results have been obtained using a rocker member with the contact point of the roller tip spaced approximately inches from the pivot point, and the contact point of the lower rocker arm spaced approximately 4 inches from the pivot point, with the two contact points spaced apart approximately 7%. inches.

The apparatus is adjusted prior to use by positioning the adjusting screw 100 so that the tolerance between the roller tip 96 and the sinker cap is as fine as possible without interfering with oscillation of the sinker cap 60 when the cylinder 46 is in the raised position.

In knitting an article, such as ladies hosiery, the cylinder is first positioned in a raised position to knit the welt portion using heavy yarn with the roller tip 96 of the rocker member 88 raised to provide a relatively large tolerance to accommodate the heavy yarn. the welt portion is knit, the cylinder drops down with an accompanying reduction in the roller tip clearancewhich holds the cylinder against floating or fluttering during the knitting of the leg portion with finer yarn. The cylinder continues to drop gradually until the heel is reached at which point it is raised to its highest posi tion, higher than the welt position, with an accompanying increase in the roller tip clearance to permit knitting of the heel using heavy yarn and an oscillating motion. The cylinder then drops to its lowest position to knit the foot portion, using fine yarn and a fine roller tip clear* ance. Finally, the cylinder is again raised to its highest; position to knit the toe portion using heavy yarn and an. oscillating motion with the relatively larger roller tipclearance.

The present invention has been described in detail above for purposes of illustration only and is not intended. to be limited by this description or otherwise except as defined in the appended claims.

I claim:

1. In a circular knitting machine of the type having a bed plate, a rotatable needle cylinder supported on a. vertically movable tube and guided by said bed plate, needles and sinkers carried on the cylinder, a sinker cap seated on top of the cylinder for controlling the movement of the sinkers, and a knitting head mounted in dependently of and directly above the cylinder, whereby yarn is fed from the knitting head to the rotating cylinder and is knit by the co-ordinated movements of the needles, sinkers and knitting head elements, and in which said tube is moved vertically to move the cylinder and vary the relative position of the needles, sinkers and;

After 6 knitting head elements, means for maintaining said needle cylinder for proper operation in its various vertical positions, said means comprising a rocker member pivotally mounted on said bed plate and having an upper arm extending upwardly over and in contact with the top of the sinker cap to prevent vertical floating or fluttering of the cylinder beyond a predetermined tolerance when the cylinder is in a raised position, said rocker member having a lower arm extending downwardly into engagement with said tube for vertical movement therewith, the length of the upper arm from the pivot to the contact with the sinker cap being greater than the length of the lower arm from the pivot to the engagement with the tube so that the contact point of the upper arm moves a slightly greater distance than the cylinder, and when. the tube and cylinder are lowered the contact point isv moved downwardly a greater distance than the cylinder, thereby reducing the floating or fluttering tolerance of the cylinder.

2. In a circular knitting machine of the type having a bed plate, a rotatable needle cylinder supported on a vertically movable tube and guided by said bed plate, needles and sinkers carried on the cylinder, a sinker cap seated on top of the cylinder for controlling the movement of the sinkers, and a knitting head mounted independently of and directly above the cylinder, whereby yarn is fed from the knitting head to the rotating cylinder and is knit by the co-ordinated movements of the needles, sinkers and knitting head elements, and in which said tube is moved vertically to move the cylinder and vary the relative position of the needles, sinkers and knitting head elements, means for maintaining said needle cylinder for proper operation in its various vertical positions, said means comprising a rocker member pivotally mounted on said bed plate and having a lower arm extending downwardly with its outer end. supported on a bracket fixed to said tube, means for urging said lower arm against said bracket, said rocker member having :an upper arm extending upwardly with its outer end in contact with the top of the sinker cap to prevent vertical floating or fluttering of the cylinder beyond a predetermined tolerance when the cylinder is in a particular vertical position, the length of said upper arm being greater than the length of the lower arm so that the outer end of the upper arm will move vertically with respect to the cylinder when the tube is moved, thereby changing the floating or fluttering tolerance of the cylinder.

3. The means for maintaining the needle cylinder of a circular knitting machine in proper operating positions according to claim 2 wherein the bracket on the tube extends laterally and the means for urging the lower arm against the bracket comprises a spring having one end secured to said lower arm and the other end secured to the knitting machine below the bracket so that the spring also serves to maintain the tube against uncontrolled vertical movement.

4. The means for maintaining the needle cylinder of a circular knitting machine in proper operating positions according to claim 2 wherein the upper arm of the rocker member has a freely rotatable roller member mounted at its outer end in contact with the sinker cap to permit rotation or oscillation of the sinker cap while maintaining a desired tolerance.

References Cited in the file of this patent UNITED STATES PATENTS 

